We propose to monitor immunologically, selected patients with breast cancer, bowel cancer, lung cancer, head and neck cancer, and malignant melanoma who are receiving treatment with combinations of cytotoxic drugs in order to ascertain whether such treatment has in some patients a selective differential suppressive effect on host immunoregulatory suppressor and effector cell mechanisms. With serial assessment points taken before, during and at intervals after chemotherapy, the kinetics of recovery of lymphocyte response to mitogenic stimulation and the effects on the rate and extent of recovery of suppressor cell mechanisms will be measured. An attempt will be made to correlate "rebound-overshoot" patterns of immune recovery when they occur with an inhibition by chemotherapy of suppressor mechanisms which may persist through the post-treatment interval and to relate these observations to the effect of chemotherapy on numbers of B-cells and T-cells, T-cell subsets (TG and TM cells) and monocytes. The effect of cytotoxic drug treatment on three other parameters of immune function in cancer patients will also be studied. The first of these, the in vitro generation of cytotoxic cells against allogeneic target cells may reflect afferent host anti-tumor immune capacity. The second, the leukocyte adherence inhibition (LAI) phenomenon is perhaps the most sensitive and specific of those in vitro correlates of cell mediated anti-tumor immune reactivity. The third, an assessment of monocyte activation by quantitation of monocyte chemiluminescence may reflect host capacity for nonspecific anti-tumor immunity. The influence of patient serum on each of these immune functions will be evaluated. The results of our investigation will provide a clearer appreciation of the immunobiological interactions between cytotoxic chemotherapy and host immune respones in human malignant diseases. The results obtained will provide the basis for improved assessments of patient prognosis and the more rational and effective scheduling of programs of treatment with chemotherapy or chemoimmunotherapy.